External rescue and recovery devices and methods for underwater vehicles

Abstract

Methods and devices are provided for rescuing and recovering underwater vehicles. In one embodiment, a system is provided that includes a modular rescue device configured to attach to an underwater vehicle, such as with a tow line. The rescue device can include one or more emergency mechanisms that can be automatically and/or manually activated to aid in detecting the location of the underwater vehicle in the event of an emergency. One exemplary emergency mechanism includes a buoyancy mechanism, e.g., an expandable lift bag, configured to be inflated with a fluid to add buoyancy force to the system to pull the underwater vehicle toward a water surface. Another exemplary emergency mechanism includes a signaling mechanism configured to signal the underwater vehicle's location.

The invention claimed is: 
     
       1. A rescue and recovery system, comprising:
 an autonomous underwater vehicle; and 
 a rescue device having:
 a submersible housing coupled to and disposed outside the autonomous underwater vehicle; 
 an emergency mechanism located within the housing and configured to be deployed upon detection of an emergency condition; 
 an actuator configured to deploy the emergency mechanism; and 
 a sensor configured to detect an emergency condition and to trigger the actuator to deploy the emergency mechanism upon detection of the emergency condition wherein the emergency condition includes at least one of exceeding a threshold dive time, falling below a threshold travel speed, the housing longitudinally oriented above a threshold angle, and exceeding a threshold dive speed; 
 
 wherein the rescue device is connected to and spaced apart from the autonomous underwater vehicle so that the rescue device is towed behind the autonomous underwater vehicle at a distance. 
 
     
     
       2. The system of  claim 1 , wherein the emergency mechanism includes at least one of a light, an expandable bag, a flare, a signal transmitter, a flag, a dye, and a GPS system. 
     
     
       3. The system of  claim 1 , further comprising a cable configured to couple the housing to the autonomous underwater vehicle. 
     
     
       4. The system of  claim 3 , wherein the cable connects to a head of the housing and a tail of the autonomous underwater vehicle to allow the housing to be towed underwater by the autonomous underwater vehicle. 
     
     
       5. The system of  claim 3 , wherein the cable is configured to have a first length extend between the housing and the autonomous underwater vehicle and a second length that is longer than the first length contained within at least one of the housing and the underwater vehicle. 
     
     
       6. The system of  claim 5 , wherein at least a portion of the cable is configured to unspool when underwater to increase a distance between the housing and the autonomous underwater vehicle. 
     
     
       7. The system of  claim 1 , wherein the housing is configured to decouple from the autonomous underwater vehicle upon detection of an emergency condition. 
     
     
       8. The system of  claim 1 , wherein the emergency mechanism includes a buoyancy mechanism, and wherein the actuator is configured to expand the buoyancy mechanism to increase a buoyancy of the housing and the autonomous underwater vehicle coupled to the housing. 
     
     
       9. The system of  claim 1 , wherein the actuator includes at least one of an R134a refrigerant, carbon dioxide, and an explosive powder. 
     
     
       10. The system of  claim 1 , wherein the sensor is located within the housing. 
     
     
       11. The system of  claim 1 , further comprising a power system located within the housing and configured to provide power to the housing independent of the autonomous underwater vehicle. 
     
     
       12. The system of  claim 11 , wherein the actuator is configured to turn on the power system upon detection of the emergency condition.